U.S. patent application number 10/920111 was filed with the patent office on 2005-01-27 for fuel injector.
Invention is credited to Hans, Waldemar.
Application Number | 20050017097 10/920111 |
Document ID | / |
Family ID | 7926431 |
Filed Date | 2005-01-27 |
United States Patent
Application |
20050017097 |
Kind Code |
A1 |
Hans, Waldemar |
January 27, 2005 |
Fuel injector
Abstract
A fuel injector for fuel injection systems of internal
combustion engines, having a valve needle which works together with
a valve seat face to form a sealing seat, has an armature acting on
the valve needle. The armature is movably guided on the valve
needle and is damped by an elastomer ring made of an elastomer. The
armature has at least one fuel channel for supplying fuel to the
sealing seat. A flat supporting ring which axially supports the
elastomer ring in the area of the outlet end of the fuel channel is
arranged between the elastomer ring and the armature.
Inventors: |
Hans, Waldemar; (Bamberg,
DE) |
Correspondence
Address: |
KENYON & KENYON
ONE BROADWAY
NEW YORK
NY
10004
US
|
Family ID: |
7926431 |
Appl. No.: |
10/920111 |
Filed: |
August 17, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10920111 |
Aug 17, 2004 |
|
|
|
09868681 |
Sep 24, 2001 |
|
|
|
6799734 |
|
|
|
|
09868681 |
Sep 24, 2001 |
|
|
|
PCT/DE00/03700 |
Oct 21, 2000 |
|
|
|
Current U.S.
Class: |
239/585.1 |
Current CPC
Class: |
Y10S 239/90 20130101;
F02M 51/0685 20130101; F02M 2200/306 20130101; F02M 61/12
20130101 |
Class at
Publication: |
239/585.1 |
International
Class: |
B05B 001/30 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 21, 1999 |
DE |
199 50 761.9 |
Claims
1-8. (Canceled).
9. A fuel injector, comprising: a valve seat face; a valve needle
working together with the valve seat face to form a sealing seat;
an elastomer ring made of an elastomer; and an armature including
at least one fuel channel and acting on the valve needle, the
armature being movably guided on the valve needle and being damped
by the elastomer ring, wherein: a longitudinal axis of the at least
one fuel channel is inclined with respect to a longitudinal axis of
the armature so that the at least one fuel channel opens radially
outside of the elastomer ring.
10. The fuel injector according to claim 9, wherein: the fuel
injector is for a fuel injection system of an internal combustion
engine.
11. The fuel injector according to claim 9, further comprising: a
bearing spring accommodated by a tangential groove, wherein: the at
least one fuel channel opens into the tangential groove on a
circumference of the armature.
12. The fuel injector according to claim 9, wherein: the elastomer
ring is an O ring.
13. The fuel injector according to claim 9, wherein: on an end face
adjacent to the elastomer ring, the armature includes a projection
that supports the elastomer ring radially.
14. The fuel injector according to claim 9, wherein: the elastomer
ring includes an elastomer having a high degree of internal damping
and a high low-temperature elasticity.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of prior U.S. patent
application Ser. No. 09/868,681 filed on Sep. 24, 2001, which is a
national stage application of PCT International Application No.
PCT/DE00/03700 filed on Oct. 21, 2000, each of which is expressly
incorporated herein in its entirety by reference thereto.
FIELD OF THE INVENTION
[0002] The present invention relates to a fuel injector.
BACKGROUND INFORMATION
[0003] U.S. Pat. No. 4,766,405 describes a fuel injector having a
valve closing body connected to a valve needle and working together
with a valve seat face designed on a valve seat body to form a
sealing seat. For electromagnetic operation of the fuel injector, a
solenoid works together with an armature connected in a
friction-locked manner to the valve needle. An additional mass is
provided in the form of a cylinder around the armature and the
valve needle and is connected to the armature by an elastomer
layer. One disadvantage is the complicated design featuring an
additional component. The large-area elastomer ring is also a
disadvantage for the variation of the magnetic field and makes it
difficult for the field lines to close and thus interferes with
achieving high attraction forces in the opening movement of the
fuel injector.
[0004] U.S. Pat. No. 4,766,405 also describes an embodiment of a
fuel injector; a cylindrical mass which is movably held and secured
in position by two elastomer rings is provided around the armature
and the valve needle for damping and reducing rebound. When the
valve needle strikes the valve seat, this second mass can move
relative to the armature and the valve needle and prevent
rebounding of the valve needle. One disadvantage of the embodiment
described there is the additional complexity and space required.
The armature itself is not isolated and its momentum thus increases
the tendency of the valve needle to rebound.
[0005] U.S. Pat. No. 5,299,776 describes a fuel injector having a
valve needle and an armature which is movably guided on the valve
needle and whose movement is limited by a first stop in the stroke
direction of the valve needle and by a second stop against the
stroke direction. Within certain limits, the axial movement play of
the armature defined by the two stops results in isolation of the
inert mass of the valve needle from the inert mass of the armature.
This counteracts within certain limits the rebound of the valve
needle from the valve seat face in closing of the fuel injector.
However, since the axial position of the armature with respect to
the valve needle is completely undefined due to the free mobility
of the armature with respect to the valve needle, rebound pulses
are prevented only to a limited extent. In particular, the design
of the fuel injector known from U.S. Pat. No. 5,299,776 does not
prevent the armature from striking the stop facing the valve
closing body in the closing movement of the fuel injector and
transmitting its momentum abruptly to the valve needle. This abrupt
transfer of momentum can cause additional rebound pulses of the
valve closing body.
[0006] It is also known from practice that the armature guided on
the valve needle can be movably secured in its position by an
elastomer ring. To do so, the armature is held between two stops,
with an elastomer ring located between the armature and the bottom
stop. However, then the problem arises that a bore through the
armature is necessary to supply fuel to the valve seat face. The
bore through the armature is provided close to the valve needle,
and the valve seat side end of the bore is partially covered by the
elastomer ring. This results in irregular pressure on the elastomer
ring and finally the bore edges result in the destruction of the
elastomer ring due to edge pressure. Furthermore, the vibrations
are induced in the unsupported elastomer ring, which also
contributes to destruction by the bore edges. This occurs
especially at low temperatures, when the elastomer enters a rigid
vitreous state.
SUMMARY OF THE INVENTION
[0007] The fuel injector according to the present invention has the
advantage over the related art that the elastomer ring is supported
axially over its full surface. Thus, there cannot be any edge
pressure on the elastomer ring. This improves the long-term
stability of the elastomer ring.
[0008] This is achieved in that the fuel injector has a flat
supporting ring between the elastomer ring and the armature,
supporting the elastomer ring axially over its entire surface and
thus also in the area of the fuel channel.
[0009] This is achieved in that the longitudinal axis of the fuel
channel is inclined to the longitudinal axis of the armature so
that the fuel channel opens radially outside the elastomer ring. In
this way, the elastomer ring is also supported over its entire
surface on an end face of the armature. In this embodiment, no
vibration is induced in the elastomer ring by fuel flowing past
it.
[0010] The supporting ring may advantageously have an integrally
molded shoulder. Therefore, the elastomer ring is also supported
radially and is protected from vibration induced by the fuel
flowing past it. Accordingly, the end face of the armature may have
a projection which provides radial protection.
[0011] A conventional inexpensive O ring may be used to advantage
as the elastomer ring.
[0012] The elastomer ring may be made of an elastomer having a high
internal damping and a great low-temperature elasticity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows an axial section through a generic fuel
injector.
[0014] FIG. 2 shows a detail of a first embodiment of a fuel
injector according to the present invention.
[0015] FIG. 3 shows a detail of a second embodiment of a fuel
injector according to the present invention in a partially cutaway
diagram.
[0016] FIG. 4 shows a detail IV from FIG. 2 on an enlarged
scale.
[0017] FIG. 5 shows a detail V from FIG. 2 on an enlarged scale in
a modified form.
[0018] FIG. 6 shows a detail VI from FIG. 3 on an enlarged
scale.
DETAILED DESCRIPTION
[0019] FIG. 1 shows a detail of a generic fuel injector 1 in a
sectional diagram to better explain the present invention. Fuel
injector 1 injects fuel into an internal combustion engine having
fuel mixture compression and spark ignition. The embodiment
illustrated here is a high pressure fuel injector opening inward
for direct injection of fuel into the combustion chamber of the
internal combustion engine.
[0020] Fuel injector 1 has a valve closing body 3 which is
connected in one piece to a valve needle 2 in this embodiment and
works together with a valve seat face designed on a valve seat body
4 to form a sealing seat. Valve seat body 4 is connected to a
tubular valve seat carrier 5 which can be inserted into a receiving
bore of a cylinder head of the internal combustion engine and is
sealed with respect to the receiving bore by a gasket 6. On its
inlet end 7, valve seat carrier 5 is inserted into a longitudinal
bore 8 of a housing body 9 and is sealed with respect to the
housing body 9 by a sealing ring 10. Inlet end 7 of valve seat
carrier 5 is under pre-tension by a threaded ring 11, with a lift
adjusting disk 14 clamped between a step 12 of housing body 9 and
an end face 13 of inlet end 7 of valve seat carrier 5.
[0021] A solenoid 15 wound onto a coil frame 16 is used for
electromagnetic actuation of fuel injector 1. When solenoid 15 is
electrically energized, an armature 17 is pulled upward until its
end face 19 on the inlet end is in contact with a step 18 of
housing body 9. The gap width between the upstream end face 19 of
armature 17 and step 18 of housing body 9 determines the valve lift
of fuel injector 1. In its stroke movement, armature 17 entrains
valve needle 2 which is connected to first stop body 20 and valve
closing body 3 which is connected to valve needle 2 because of the
contact of its upstream end face 19 with a first stop 21 provided
on a first stop body 20. Valve needle 2 is welded to first stop
body 20 by a weld 22. Valve needle 2 moves against a restoring
spring 23 which is secured between an adjusting sleeve 24 and first
stop body 20.
[0022] Fuel flows through an axial bore 30 of housing body 9 and at
least one fuel channel 31, which is provided in armature 17 and is
designed here as an axial bore, as well as through axial bores 33
provided in a guide disk 32, into an axial bore 34 of valve seat
carrier 5 and from there to the sealing seat (not shown) of fuel
injector 1.
[0023] Armature 17 is movable between first stop 21 of first stop
body 20 and a second stop 26 designed on a second stop body 25,
with armature 17 in this embodiment being held in contact with
first stop 21 by a bearing spring 27 in the resting position, so
that a gap is formed between armature 17 and second stop 26, thus
permitting a certain movement play of armature 17. Second stop body
25 is secured on valve needle 2 by a weld 28.
[0024] Due to the movement play of armature 17 between stops 21 and
26, isolation between the inert masses of armature 17 and valve
needle 2 with valve closing body 3 is achieved. Therefore, in the
closing movement of fuel injector 1, only the inert mass of valve
closing body 3 and valve needle 2 strikes against the valve seat
face, in which case armature 17 is not decelerated abruptly when
valve closing body 3 strikes the valve seat face, but instead it
moves further in the direction of second stop 26. The isolation of
armature 17 from valve needle 2 improves the dynamics of fuel
injector 1. However, end face 29 of armature 17 on the spray end
striking second stop 26 does not cause any valve rebound. This is
achieved through an elastomer ring 35 shown in FIG. 2 between
second stop body 25 and armature 17. Bearing spring 27 may
optionally also be eliminated because of the damping by elastomer
ring 35.
[0025] FIG. 2 shows a detail of armature 17 with valve needle 2 of
a fuel injector according to the present invention; elements that
have already been described are shown with the same reference
numbers to facilitate a correlation.
[0026] The drawing shows armature 17 of fuel injector 1 according
to the present invention having fuel channel 31, valve needle 2,
second stop body 25 welded onto valve needle 2 by weld 28 and
second stop 26, as well as end face 29 opposite second stop 26.
Valve needle 2 is welded to first stop body 20 by weld 22.
[0027] FIG. 4 shows an embodiment according to the present
invention as illustrated in detail IV from FIG. 2 on an enlarged
scale. Between end face 19 of armature 17 and second stop 26 there
is an elastomer ring 35, a flat supporting ring 36 between
elastomer ring 35 and armature 17 supporting elastomer ring 35 over
its entire area, i.e., in particular also in the area of fuel
channel 31, and thus preventing edge pressure at the edge of fuel
channel 31.
[0028] FIG. 5 shows an alternative embodiment according to the
present invention as illustrated in detail V from FIG. 2 on an
enlarged scale. Between end face 19 of armature 17 and second stop
26 there is an elastomer ring 35, designed as an O ring 37 in this
embodiment. This O ring 37 is supported by flat supporting ring 36
over its entire area, i.e., also in the area of fuel channel 31 in
particular, flat supporting ring 36 also supporting O ring 37
radially by an integrally molded, axially angled shoulder 39. Thus
a commercially available component such as O ring 37 can be
inexpensively used. Inducement of vibration in O ring 37 by fuel
passing by it is prevented by the larger coverage of O ring 37,
which also extends laterally. This counteracts destruction of
elastomer ring 35 due to the edge pressure on fuel channel 31 and
due to inducement of vibration.
[0029] In particular due to the radial support of O ring 37, use of
an elastomer with a greater internal damping is possible. High
damping by an elastomer is usually also associated with a low
elasticity modulus. Since O ring 37 is protected against the forces
mentioned above which shorten the lifetime of an O ring 37, such an
elastomer may be used for O ring 37 without having a negative
effect on the service life of O ring 37.
[0030] A low elasticity modulus of an elastomer at low temperatures
usually results in an even greater sensitivity to edge pressure and
inducement of vibration at the operating temperature. Therefore, in
the embodiment described here as an example, it is also possible to
achieve a great low-temperature elasticity of O ring 37 and thus
favorable operating performance of fuel injector 1 at low
temperatures, e.g., after a cold start of the engine.
[0031] FIG. 3 shows an enlarged detail of armature 17 and valve
needle 2 of a fuel injector 1 according to another embodiment of
the present invention.
[0032] FIG. 3 shows armature 17 of fuel injector 1 according to the
present invention, valve needle 2, second stop body 25 welded by
weld 28 onto valve needle 2 and having a second stop 26, and end
face 29 of armature 17 opposite second stop 26. Valve needle 2 is
welded by weld 22 to first stop body 20. The at least one fuel
channel 31 opens radially outside of elastomer ring 35 because it
is inclined with respect to the axis of valve needle 2.
[0033] Elastomer ring 35 which is designed as O ring 37 is shown in
FIG. 6 with its area facing the environment according to detail VI
from FIG. 3 in an enlarged view. In the embodiment illustrated
here, fuel channel 31 opens into a tangential groove 36 which
accommodates bearing spring 27. This embodiment is especially
advantageous because there is no inducement of vibration of O ring
37 by fuel flowing past it, and no enlargement of the diameter of
armature 17 is necessary due to the inclination of fuel channel 31
to the axis of valve needle 2.
[0034] In the embodiment illustrated in FIG. 6, end face 29 of
armature 17 has a projection 40. Due to the fact that O ring 37 is
also covered laterally, it is possible to use an elastomer having a
high internal damping and therefore a relatively low elastic
modulus without any negative effect on its service life. The fact
that O ring 37 is also supported radially prevents it from swelling
forward and thus prevents the destruction of O ring 37 by
compressive forces.
[0035] It is thus also possible to achieve a great low-temperature
elasticity of O ring 37 without causing a shortened service life at
the operating temperature of fuel injector 1.
* * * * *